BREEDERS are being urged to have their mares tested for Equine Viral Arteritis [EVA] and to make themselves aware of the EVA protocols that have been put in place by stallion farms before they send their mare for covering this season.

EVA is a venereal and respiratory-spread disease which can result in pregnancy loss and affect stallion fertility. Ongoing surveillance reports from the Irish Equine Centre have consistently shown that Ireland is free of EVA. This surveillance is essential for maintaining the industry’s freedom of horse movements. EVA is a notifiable disease and any incursion would have immediate international trade consequences. Any suspicion of incursion and all positive tests must be reported to the Department of Agriculture.

The approved EVA vaccine, Artervac, which has been used to protect stallions in Ireland, the EU and the UK from this disease for many years is not available this year and attempts to have a substitute vaccine imported are ongoing. In the meantime, individual stallion farms have taken different views on the degree of protection from EVA that they require in relation to the timing of EVA samples, prior to mating.

“All breeders must therefore make certain that they understand the individual requirements of each of the stallion farms to which they intend to send their mares,” said Dr Des Leadon, veterinary advisor to the Irish Thoroughbred Breeders’ Associations [ITBA] and the European Federation of Thoroughbred Breeders’ Associations [EFTBA].

Protective measures

Explaining the background to the situation, Leadon said: “Ireland has always protected itself from disease, as have other jurisdictions, by two measures – complying with the International Codes of Practice and through vaccination. Unfortunately there was a failure of production of the vaccine by the international pharma company Zoetis. The ITBA first became aware of this possible failure in October 2023 and asked the Department of Agriculture if they would consider the importation of alternative vaccines.”

The Department explored the possibility of importing a comparable activated vaccine from Japan but, for many reasons, this proved to be impractical. The ITBA, and its European counterparts, then sought permission for an emergency import licence of the live EVA vaccine named Arvac from the USA.

Leadon said: “We were of the view that the absence of a vaccine significantly increased the risks of EVA incursion into Ireland, and therefore every effort should be made to allow for Arvac importation.”

The Department considered this request in consultation with Zoetis and the Health Products Regulatory Authority between October and December.

However, according to Leadon, there was some “inappropriate advice” of uncertain origin that those who administer the Arvac vaccine would have to wear full personal protective equipment, akin to that used during Covid, and that stallions would have to go into mandatory four-week quarantine post-vaccination.

The ITBA sought guidance in this regard from the United States Department of Agriculture and, in particular, from Dr Rusty Ford of the State Veterinarians Office in Kentucky. Dr Ford produced the official records of EVA vaccination with Arvac from 1985 to the present day.

“These records demonstrated that more than 13,000 elite stallions in Kentucky had been vaccinated with Arvac in that period,” Leadon said. “Importantly, the uptake and usage of this vaccine among the elite stallions in Kentucky was virtually 100%.”

This information was relayed to the Department of Agriculture by the ITBA. It was similarly relayed to the French ministry by the French TBA and to the German state authorities by the German breeders’ federation. It was also circulated to all EFTBA member countries through chairman Joe Hernon and the EFTBA offices here in Ireland. A decision on possible emergency licence facilitation by the Department of Agriculture here is currently awaited.

In the meantime, the ITBA has advised all its members of the increased vulnerability to EVA that now exists in the absence of vaccinal protection of our stallions, and de facto from stallions spreading the disease into the mares in which they come into contact, and/or vice versa.

Leadon added: “We also feel and have advised the Department that the absence of any compliance with the International Codes of Practice in the non-thoroughbred sector represents a potential Achilles heel in the present context”. Unlike the situation in Ireland, compliance with the International Codes of Practice in France and Germany is mandatory for all horse breeding and is a legal requirement.

“It is essential that everybody involved in this industry accepts they have a personal responsibility to protect our ability to declare our ongoing freedom from EVA and to protect our massive national investments from the incursion of this disease,” Leadon added. “It is therefore very important that all breeders comply with the International Codes of Practice by carrying out EVA testing of their mares prior to breeding”.

Web: See Industry Matters section of website for 2024 International Codes of Practice